Hydraulic lift jack

ABSTRACT

The lift jack has an upright cylinder operatively associated with a lift piston assembly, the full surface area of the underside of which is utilized in the raising of the piston assembly; and only a portion of the surface area of the top side is utilized in the lowering of the piston assembly. With fluid under a constant pressure and volume rate supplied from a single source, the piston assembly is slowly elevated with a maximum lifting pressure and quickly lowered with an appreciably reduced pressure.

United States atet 11113,622,124

[72] Inventors Kenneth R. Sldles; 2,965,375 12/1960 Hamilton 254/93 R XDwayne R.Sidles,both 01314 No. 15th St., 3,168,853 2/1965 Prince 91/167Esthervllle, Iowa 51334 3,353.352 l 1/1967 Gardner 92/108 lzl 1 Appl38032 Primary Examiner-Othell M. Simpson (22] Filed [45] Patented May18, 1970 Nov. 23, 1971 [54] HYDRAULIC LIFT JACK 93 HP, 93 L; 60/52 HA,52 HD; 92/108; 91/167 [56] References Cited UNITED STATES PATENTSAttorney-Rudolph L. Lowell preciably reduced pressure.

PAIENTEDuuv 23 l8?! 3,622,124

SHEET 1 [1F 2 m vewrom KENNETH A. 5/01. 5 DW/WNE P. 5/01. ES

HYDRAULIC LIFI JACK SUMMARY OF THE INVENTION The lift jack is of asimple and compact construction efficient in operation to exert amaximum lifting pressure with a slow lift and a reduced pressure with afast drop from a fluid source of uniform volume and pressure. Where theobject being lifted is blocked in an elevated position the fast dropaction of the lift jack results in time and labor savings by virtue ofits quick availability for successive lift operations such as arecommonly required in a house moving operation.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of thelift jack of this invention;

FIG. 2 is a longitudinal sectional view of the lift jack of FIG. 1 shownin a fully raised position and in assembly relation with a fluid controlsystem;

FIG. 3 is a longitudinal sectional view of the lift jack in a partiallyraised position showing the flow of fluid therein during an elevatingoperation;

FIG. 4 is illustrated similarly to FIG. 3 and shows the flow of fluidthrough the lift jack during a lowering operation; and

FIG. 5 is a top plan view of the lift jack shown in FIG. 1.

DETAIL DESCRIPTION OF THE INVENTION With reference to FIGS. 1 and 2 ofthe drawings the lift jack of this invention, designated generally as10, is shown as including a base member 11 to which is secured the lowerend of an upright cylinder member 12. Extended axially of and within thecylinder 12 is a tubular fluid carrying member or manifold 13 that isalso secured at its lower end to the base member 11. The manifold 13 hasfluid openings 14 adjacent its upper end and a fluid opening 16 in itslower end that is in registration with a fluid passage 17 formed in thebase member 11. A second fluid passage 18 in the base member is open tothe lower end of the cylinder member 12.

Operatively associated with the cylinder member 12 is a piston assembly19 that includes a piston unit 21 provided with a tubular piston rod 22which is concentrically spaced about the fluid carrying manifold 13. Thepiston unit 21 has a central ring portion 23 located within and attachedto the lower end of the piston rod 22 with its inner peripheral surfacein sliding engagement with the outer peripheral surface of the fluidcarrying member 13. An outer ring portion 24 of the piston unit 21 ispositioned about and secured to the lower end of the piston rod 22 withthe outer peripheral surface thereof in sliding engagement with theinner peripheral surface of the cylinder member 12.

The tubular piston rod 22 is guidably mounted for reciprocal movementrelative to the cylinder member 12 by a closure means 26 for the upperend of the cylinder. This closure means includes a central ring orannular section 27 that is secured about and adjacent the upper end ofthe manifold member 13 so as to be in slidable engagement with the innerperipheral surface of the piston rod sidewall 28. An outer annularsection 29 of the closure means 26 is secured within and adjacent theupper end of the cylinder member 12 for slidable engagement with theouter peripheral surface of the piston rod sidewall 28. It is seen,therefore, that the enclosure means 26 is f 1:: ed with a circular slot31 of a width slightly greater than the thickness of the piston rodsidewall 28 so as to slidably receive the sidewall therein forretraction and extension of the piston rod 22 relative to the cylindermember 12.

As thus far described, it is seen that when the piston assembly 19 is inits lowered position, shown in dotted lines in FIG. 1, the cylindermember 12 is divided by the manifold member 13 and the piston rod 22into a pair of spaces 32 and 33, which are concentrically arranged aboutthe manifold member 13. However, on extension of the piston assembly 19outwardly from the cylinder member 12 (FIGS. 3 and 4) there is formedwithin the cylinder only a single space 34 through which the fluidcarrying tube or manifold 13 is axially extended. The spaces 32 and 34constitute expansible fluid chambers and the space 33 an expansible airchamber. The openings 14in the fluid carrying member 13 are thus open tothe fluid chamber 32 and the fluid passage 18 in the base member 11 isopen to the fluid chamber 34.

A lift sleeve 36 of a cylindrical shape is guidably mounted about thecylinder member 12 for relative longitudinal movement (FIGS. 3 and 5).Secured to and extended radially from adjacent the lower end of the liftsleeve is a load supporting platform 37. The upper end of the liftsleeve 36 is connected to the upper end of the piston rod 22 by a commoncover plate 38 which is secured to the lift sleeve by weldments 39 andthe piston rod by bolts 40. The piston rod 22 and the lift sleeve 36 arethus longitudinally and rotatably movable as a unitary assembly relativeto the cylinder member 12.

The lifi jack 10 is hydraulically operated from a single pump 41 througha two-way hydraulic valve 42 (FIG. 1). The pump 41 may be driven by anelectric motor or from the power takeoff of a truck or like vehicle. Theinlet 43 of the pump 41 is connected by a line 44 with an oil reservoir46. The outlet 47 of the pump 41 delivers oil under pressure to thecontrol valve 42 for selective flow into one of a pair of fluid lines 48or 49 which are in fluid connection with the fluid passages 17 and 18,respectively, in the base member 11. The control valve 42, which is of aconventional type, has an exhaust line 51 connected to the reservoir 46.

In the operation of the lift jack 10, assume the piston assembly 19 isto be elevated from its lowered position shown in dotted lines inFIG. 1. On movement of the control handle 52 of the control valve 42 toits dotted line position, indicated at 52a in FIG. 2, fluid underpressure from the pump 41 is supplied to the fluid line 49 for admissioninto the lower end of the cylinder member 12 (FIG. 3). This fluid actsagainst the under side of the total area of the piston unit 21 so that amaximum fluid pressure is obtained for extending the piston rod 22 toelevate the lift sleeve 36.

Concurrently with the admission of oil into the fluid chamber 34 of thecylinder 12 through the passage 17, oil is exhausted from the fluidchamber 32 and into the reservoir 46 through the openings 14 of thefluid carrying member 13, and then downwardly and outwardly from themember 13 into the passage 18, fluid line 48 and control valve 42 forflow through the exhaust line 51 to the reservoir 46. The elevation ofthe lift sleeve 36 (FIG. 2) is limited by engagement of the annularportion 24 of the piston unit 21 with the outer annular section 29 ofthe closure means 26 for the cylinder 12. The elevated position of thelift sleeve 36 is retained by returning the handle 52 of the controlvalve 42 to its full line position in FIG. 2.

To lower the lift sleeve 36 from its elevated position of FIG. 2, thehandle 52 is moved to its dotted line position 52b so as to reverse thetravel of the fluid through the fluid lines 48 and 49. As a result,fluid under pressure from the supply line 48 (FIG. 4) is admitted intothe fluid carrying member 13 for flow into the fluid chamber 32 so as toact only against the upper surface of the piston unit portion 23.Concurrently with the admission of fluid under pressure into the fluidchamber 32, fluid is exhausted from the fluid chamber 34 of the cylindermember 12 through the passage 18, fluid line 49, control valve 42 andexhaust line 51 into the reservoir 46. When the valve handle 52 is inits neutral full line position shown in FIG. 1, fluid from the pump 41is bypassed through the valve 42 and the exhaust line 51 into thereservoir 46.

With the pump 41 providing a constant volume rate of fluid at a uniformpressure, the piston assembly 19 is moved downwardly at an acceleratedrate. This action occurs by virtue of the piston rod 22 functioning as amovable cylinder relative to a stationary piston member constituted bythe center section 27 of the closure means 26. However, in the elevationof the lift sleeve 36, the piston rod 22 and piston assembly l9 operatein a usual manner relative to the cylinder member 12 so as to utilizethe overall area of the piston assembly 19 for elevating purposes. Thelift jack 10 thus provides for a slow lift action with a maximum pistonpressure and a fast drop action with a reduced piston pressure.

We claim:

l. A hydraulic lift jack comprising:

a. a base member,

b. a cylinder secured to and projected upwardly from said base member,

c. an upright fluid-carrying member with a fluid opening at each endthereof secured to said base member and projected axially upwardlythrough said cylinder,

d. a lift assembly including a pair of circular inner and outer sleevemembers concentrically arranged relative to said fluid-carrying memberwith the inner member within the cylinder and the outer memberpositioned about and in guidable engagement with said cylinder,

e. a piston member for said cylinder secured to the lower end of saidinner sleeve member with said fluid-carrying member slidably extendedtherethrough,

f. a closure means for the upper end of said cylinder having a circularslot therein for slidably receiving therethrough the sidewall of theinner sleeve member,

g. a source of fluid under pressure, and

h. means for supplying the fluid from said source to the underside ofsaid piston member concurrently with the exhaust of fluid from saidinner sleeve member downwardly through said fluid-carrying member, whensaid lift assembly is to be elevated, and for supplying fluid from saidsource upwardly through said fluid-carrying member and into said innersleeve member to the upper side of that portion of the piston memberdefined by the cross-sectional area of the inner sleeve memberconcurrently with the exhaust of fluid from the underside of the pistonmember, when said lift assembly is to be lowered.

2. A hydraulic jack comprising:

a. a base member,

b. a cylinder secured to and projected upwardly from said base member,

c. a piston assembly for said cylinder including a tubular piston rodand a piston member secured to the lower end of said piston rod,

d. a lift member guidably mounted about said cylinder for relativelongitudinal and rotatable movement,

e. means connecting together said lift member and piston rod for unitarymovement,

f. a closure means for the upper end of said cylinder member havingcircular slot therein for slidably receiving therethrough the sidewallof said piston rod,

. an upright fluid carrying member secured to said base member axiallyof said cylinder member and slidably extended through said piston memberand into said piston rod for attachment of the upper end thereof to saidclosure means, said fluid carrying member having a fluid opening at eachend thereof,

. a source of fluid under pressure, and

. means for supplying fluid from said source into the lower end of saidcylinder for application against the lower side of said piston memberconcurrently with the exhaust of fluid from within the piston roddownwardly through said fluid-carrying member, when said lift member isto be elevated, and for supplying fluid from said source upwardlythrough said fluid-carrying member and into said piston rod forapplication against the upper side of that portion of the piston memberdefined by the cross-sectional area of the piston rod concurrently withthe exhaust of fluid from the lower end of the cylinder, when said liftmember is to be lowered.

3. The hydraulic jack according to claim 2 wherein:

a. said closure means includes a central circular portion secured tosaid fluid-carrying member having an outer peripheral surface inslidable engagement with the inner peripheral surface of the sidewall ofsaid piston rod, and an annular portion secured to said cylinder havingan inner peripheral surface in slidable engagement with the outerperipheral surface of the sidewall of said piston rod.

4. A hydraulic jack comprising:

a. a base member,

b. a cylinder projected upwardly from said base member, c. a pistonassembly including a pair of concentrically arranged inner and outersleeve members, said outer sleeve member mounted about and in bearingengagement with said cylinder member and said inner sleeve memberlocated in a concentrically spaced relation within said cylinder member,

d. means connecting said sleeve members at the upper ends thereof forunitary longitudinal and rotatable movement relative to said cylinder,

e. closure means for the upper end of said cylinder having portions inslidable engagement with inner and outer surfaces of the sidewall ofsaid inner sleeve member,

a piston member for said cylinder secured to the lower end of said innersleeve member, said piston member having a central opening therein,

g. a fluid manifold secured to said base member and projected axially ofsaid cylinder upwardly through the central opening in said piston memberand into said inner sleeve member for attachment to one of said portionsof said closure means, said fluid manifold having a fluid opening ateach end thereof,

h. a first fluid supply and exhaust line connected to the lower end ofsaid cylinder member,

i. a second fluid supply and exhaust line connected with the opening atthe lower end of said manifold, and

j. a source of fluid under pressure,

it. means for selectively controlling the supply of fluid to and theexhaust of fluid from said first and second fluid lines, whereby saidpiston assembly is elevated when fluid under pressure from said firstline is applied against the underside of said piston member concurrentlywith the exhaust of fluid from within said inner sleeve memberdownwardly of said manifold and through said second fluid line, and islowered when fluid under pressure from said second line is directedupwardly of said manifold and into said inner sleeve member to actagainst the upper side of only that portion of the piston member whichcloses the lower end of the inner sleeve member, concurrently with theexhaust from the lower end of said cylinder through said first fluidline.

a: e n w e

1. A hydraulic lift jack comprising: a. a base member, b. a cylindersecured to and projected upwardly from said base member, c. an uprightfluid-carrying member with a fluid opening at each end thereof securedto said base member and projected axially upwardly through saidcylinder, d. a lift assembly including a pair of circular inner andouter sleeve members concentrically arranged relative to saidfluidcarrying member with the inner member within the cylinder and theouter member positioned about and in guidable engagement with saidcylinder, e. a piston member for said cylinder secured to the lower endof said inner sleeve member with said fluid-carrying member slidablyextended therethrough, f. a closure means for the upper end of saidcylinder having a circular slot therein for slidably receivingtherethrough the sidewall of the inner sleeve member, g. a source offluid under pressure, and h. means for supplying the fluid from saidsource to the underside of said piston member concurrently with theexhaust of fluid from said inner sleeve member downwardly through saidfluid-carrying member, when said lift assembly is to be elevated, andfor supplying fluid from said source upwardly through saidfluid-carrying member and into said inner sleeve member to the upperside of that portion of the piston member defined by the cross-sectionalarea of the inner sleeve member concurrently with the exhaust of fluidfrom the underside of the piston member, when said lift assembly is tobe lowered.
 2. A hydraulic jack comprising: a. a base member, b. acylinder secured to and projected upwardly from said base member, c. apiston assembly for said cylinder including a tubular piston rod and apiston member secured to the lower end of said piston rod, d. a liftmember guidably mounted about said cylinder for relative longitudinaland rotatable movement, e. means connecting together said lift memberand piston rod for unitary movement, f. a closure means for the upperend of said cylinder member having a circular slot therein for slidablyreceiving therethrough the sidewall of said piston rod, g. an uprightfluid carrying member secured to said base member axially of saidcylinder member and slidably extended through said piston member andinto said piston rod for attachment of the upper end thereof to saidclosure means, said fluid carrying member having a fluid opening at eachend thereof, h. a source of fluid under pressure, and i. means forsupplying fluid from said source into the lower end of said cylinder forapplication against the lower side of said piston member concurrentlywith the exhaust of fluid from within the piston rod downwardly throughsaid fluid-carrying member, when said lift member is to be elevated, andfor supplying fluid from said source upwardly through saidfluid-carrying member and into said piston rod for application againstthe upper side of that portion of the piston member defined by thecross-sectional area of the piston rod concurrently with the exhaust offluid from the lower end of the cylinder, when said lift member is to belowered.
 3. The hydraulic jack according to claim 2 wherein: a. saidclosure means includes a central circular portion secured to saidfluid-carrying member having an outer peripheral surface in slidableengagement with the inner peripheral surface of the sidewall of saidpiston rod, and an annular portion secured to said cylinder having aninner peripheral surface in slidable engagement with the outerperipheral surface of the sidewall of said piston rod.
 4. A hydraulicjack comprising: a. a base member, b. a cylinder projected upwardly fromsaid base member, c. a piston assembly including a pair ofconcentrically arranged inner and outer sleeve members, said outersleeve member mounted about and in bearing engagement with said cylindermember and said inner sleeve member located in a concentrically spacedrelation within said cylinder member, d. means connecting said sleevemembers at the upper ends thereof for unitary longitudinal and rotatablemovement relative to said cylinder, e. closure means for the upper endof said cylinder having portions in slidable engagement with inner andouter surfaces of the sidewall of said inner sleeve member, f. a pistonmember for said cylinder secured to the lower end of said inner sleevemember, said piston member having a central opening therein, g. a fluidmanifold secured to said base member and projected axially of saidcylinder upwardly through the central opening in said piston member andinto said inner sleeve member for attachment to one of said portions ofsaid closure means, said fluid manifold having a fluid opening at eachend thereof, h. a first fluid supply and exhaust line connected to thelower end of said cylinder member, i. a second fluid supply and exhaustline connected with the opening at the lower end of said manifold, andj. a source of fluid under pressure, k. means for selectivelycontrolling the supply of fluid to and the exhaust of fluid from saidfirst and second fluid lines, whereby said piston assembly is elevatedwhen fluid under pressure from said first line is applied against theunderside of said piston member concurrently with the exhaust of fluidfrom within said inner sleeve member downwardly of said manifold andthrough said second fluid line, and is lowered when fluid under pressurefrom said second line is directed upwardly of said manifold and intosaid inner sleeve member to act against the upper side of only thatportion of the piston member which closes the lower end of the innersleeve member, concurrently with the exhaust from the lower end of saidcylinder through said first fluid line.